Naoto Adachi is a Japanese actor and voice actor born on August 21, 1993, in Tokyo, Japan. He began his career in the entertainment industry as a child actor in 1999 at the age of six. He is affiliated with the Theatre Academy talent agency.

Adachi's career spans live-action television dramas, films, and voice acting for anime and video games. He gained early attention through appearances in television dramas such as Ultraman Dyna, The Queen's Classroom, and Fugoh Keiji. His live-action film credits include a role in the 2004 movie NIN×NIN: Ninja Hattori-kun THE MOVIE.

In anime, Adachi is best known for voicing the role of Prince Chagum in the 2007 television series Moribito: Guardian of the Spirit. His other notable anime voice roles include Shuta in the TV series Capeta, Ryohei Jinnouchi in the acclaimed animated film Summer Wars, and roles in series such as Ghost Hound, Michiko & Hatchin, and Mushishi. He has also contributed voices to animated films including Kappa no Coo to Natsuyasumi and Colorful. His work in video games includes providing the voice for the character Niya in The Sky Crawlers: Innocent Aces.

Adachi has demonstrated versatility as a performer, also appearing in stage productions such as the play Akasatana. Throughout his career, he has collaborated on multiple projects with director Keiichi Hara and voice actor Yokokawa Takahiro, including the films Kappa no Coo to Natsuyasumi, Summer Wars, and Colorful.